1. Field of the Invention
The present invention relates to a driving control apparatus that executes driving control of a vehicle by selecting a vehicle that is traveling in front of the vehicle and followed by that vehicle.
Priority is claimed on Japanese Patent Application Nos. 2004-94111 and 2004-94112, filed Mar. 29, 2004, the contents of which are incorporated herein by reference.
2. Description of Related Art
Conventionally, an automatic start/stop apparatus for a vehicle has been used in order to reduce stress on the driver who has to often start or stop a vehicle following the preceding vehicle in a traffic jam, for example. Such an apparatus that executes driving control of a vehicle by setting a preceding vehicle that travels in front of a vehicle and the vehicle follows. More specifically, the apparatus determines the relationship between an inter-vehicle distance to the preceding vehicle detected by inter-vehicle distance detecting means and an inter-vehicle distance that is required to ensure safety detected by a safe inter-vehicle distance detecting means, and decelerates the vehicle when the relationship in a deceleration region whereas accelerating the vehicle when the relationship in an accelerating region. Since this apparatus automatically repeats acceleration and deceleration of the vehicle following the preceding vehicle, it can reduce stress on the driver (for example, Japanese Unexamined Patent, First Publication No. S60-19208).
In addition to an automatic start/stop control function that automatically starts or stops the vehicle in response to a start or stop of the preceding vehicle, some conventional automatic start/stop apparatuses are equipped with an adaptive cruise control function that automatically makes the vehicle travel following the preceding vehicle while keeping a certain distance between the preceding vehicle when both the vehicle and the preceding vehicle travel at a speed greater than a predetermined value. In such an apparatus, for example, the automatic start/stop control function keeps controlling the vehicle to the point in which the vehicle stops while the adaptive cruise control function terminates the control when the vehicle reaches the lower limit speed to execute the adaptive cruise control function. In this manner, since the automatic start/stop control function and the adaptive cruise control function are different in terms of control, it is required for a driver to recognize which of the control modes is currently executed.
Therefore, in a conventional driving control apparatus, instead of automatically switching between the automatic start/stop control function and the adaptive cruise control function, the control is terminated at the point when the traveling speed of the vehicle reaches to a speed for switching between the control modes, and the driver needs to instruct the start of the adaptive cruise control. Thus, the driver easily recognizes which of the control modes is currently executed (i.e., the automatic start/stop control, or the adaptive cruise control). Therefore, the driver may experience discomfort because the driving control is temporality halted until the operation by the driver that instructs the adaptive cruise control is detected after the vehicle reaches the speed for switching between the automatic start/stop control function and the adaptive cruise control function, or because the driving control may be terminated even when the driver wants to switch the modes.